I'm afraid i'll lose this game of chess. i ( play) very badly. i much better ( play)

I played very badly. I can play much better или
I played very badly. I could have played much better или
I played very badly. I should have played much better.

Второе предложение зависит от того, что вы хотите сказать: Я могу играть лучше или Я мог бы сыграть лучше или Я должен был сыграть лучше